Acoustic energy reflections from deep seabed layers in seismic reflection surveys

Abstract

Data from marine seismic reflection surveys are generally used to study the composition of the seabed 100s to 1000s of meters below the seafloor. These surveys consist of an airgun array that broadcasts an impulsive signal towards the seafloor, the reflections of which are measured by towed hydrophone streamers and used to invert for geophysical properties. The abundance of data from these surveys provides many opportunities to conduct acoustic analyses and to utilize data-driven approaches. Here, the extensive datasets are used for analyzing the impacts of seabed characteristics on the acoustic fields in the water column. Various seabed components are considered and their influence on the acoustic field quantified. It is shown that layers well below the seafloor can contribute up to 50% of the acoustic energy reflected into the water column at frequencies below 100 Hz and ranges approximately three times the channel depth. Additionally, non-intuitive relationships between layer depths and acoustic energy are explored. [Work supported by ONR.]